This invention relates to a lamp base, particularly to one with a structure of letting connecting power wires not pulled off by external force, not loosening off the terminals, very safe to use and convenient to combine.
A known conventional lamp base shown in FIG. 1, has a lamp base body 10 made of insulating material, a lamp socket 20 with threads for a lamp to engage with, a housing for preventing dirt, and a cap 40 provided with a wire hole 401.
The lamp base 10 has two terminals 101, 102 for connecting two power wires 50 by means of screws or inserting holes. In this example screw connection is shown. The lamp base 10 further has a switch 103 fixed transversely for turning on and off the lamp. And a switch has various structures to handle, such as by turning, pushing or pulling, or with no switches. No matter what structure it may be, its function is the same cap 40 is usually made of metal for good appearance. So an insulating cylinder 301 and am insulating gasket 402 have to be provided respectively to prevent dirt or any bit of miscellaneous matter to enter the lamp base to stick to the two terminals to cause bad contact or unsteady current.
Further, as for the known conventional lamp base and the power wires 50, their connecting mode and the connected condition are shown in FIG. 2. The power wires 50 firstly pass through the wire hole 401 and the gasket 402 of the cap 40, two naked ends connected to the two terminals 101, 102. Generally, a knot 501 is made to the power wires 50 to prevent the same from loosening off or becoming bad contact, for the power wires 50 are connected to the terminals 101, 102. Function of the know conventional structure is to secure the power wires 50 and more securely locating the power wires 50 by sandwiched between the upper surface of the lamp base body 10 and the bottom of the insulating gasket 402. Thus, should the power wires be pulled by exterior force, the knot 501 receives the force, not letting the naked points directly pulled off the terminals 101, 102.
However, the known conventional connecting mode has been found not really avoiding the connect disadvantages mentioned above, but on the contrary involving difficulty in assembly. A first point is inconvenience of assembling in preparing the length of the power wires 50 so as to connect with the terminals 101, 102. A second point is the tightness and the size of the knot 501, impossible to connect with in case of too short, and difficult to close the cap 40 in case of too large, resulting in extreme difficulty in assembling. In addition, in making a knot, a metal wire inside an insulating tube is bent to disfigure, causing bad transmission or unstableness of electric current, if worse. So this kind of knot is not correct usage of electricity.